Substrate processing apparatus

ABSTRACT

The substrate processing apparatus has an enclosure structure enclosing a substrate support member to define a processing space. The enclosure structure has an opening closed by a shutter. A processing fluid supply unit, which supplies processing fluid, such as chemical liquid, is accommodated in a housing. The processing fluid supply unit accommodated in the housing is advanced into the processing space through the opening of the enclosure structure to feed the processing fluid onto the substrate supported by the substrate support member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a substrate processing apparatus forprocessing substrates, such as semiconductor wafers or glass substratesfor LCDs by a cleaning process or the like.

2. Description of the Related Art

A semiconductor device manufacturing process uses a substrate cleaningsystem for cleaning semiconductor wafers (hereinafter referred to simplyas “wafers”) with a cleaning liquid, such as a chemical solution or purewater, to remove contaminants, such as particles, organic contaminantsand metallic impurities, from the wafers. There are various known batchsubstrate cleaning apparatus and known single-wafer substrate cleaningapparatus for such a substrate cleaning system. A prior artsubstrate-cleaning apparatus disclosed in Japanese patent laid-openpublication “JP Hei08-78368 A” has a plate disposed close to the surfaceof a wafer, and supplies a processing liquid or a processing gas intothe gap between the surface of the wafer and the plate for a cleaningprocess. This prior art substrate-cleaning apparatus has an advantage inthat the same is capable of achieving a cleaning process at a lowconsumption of the processing liquid or the processing gas.

In this prior art substrate cleaning apparatus, however, a processingmedium supply means for supplying the processing liquid or theprocessing gas to the substrate is disposed in a substrate-processingspace and is exposed to a substrate-processing atmosphere. Therefore, itis possible that the substrate-processing atmosphere produced by theprocessing medium supply means for supplying the processing liquid orthe processing gas diffuses and exerts bad influence on the processedsubstrate. It is also possible that the processing medium supply meansis contaminated with an atmosphere of the processing liquid or theprocessing gas diffused during a substrate-processing process, in whichthe processing medium supply means is held in a waiting state. If thesubstrate cleaning apparatus is provided with a plurality of processingmedium supply means, it is possible that the plurality processing mediumsupply means exert bad influences on each other.

In addition, it is also possible that the processing atmosphere of theprocessing liquid remains in a cleaning unit after the completion of thecleaning process, and the processing liquid remaining in the processingunit exerts bad influences on the processed wafer. A high-temperatureprocessing liquid is liable to remain in mist in an upper part of thecleaning unit and hence it is highly possible for the mist of theprocessing liquid to exert bad influences on the wafer.

A substrate-processing atmosphere of the processing liquid is liable toleak from the conventional substrate processing device when a substrateis loaded into or unloaded from the substrate processing device, andthere is the possibility that a carrying device and such included in thecleaning system are corroded by the leaked substrate-processingatmosphere of the processing liquid. Therefore the carrying device andsuch must be rust-proofed. However, most carrying devices and such areformed from explosion-proof materials. Therefore, materials for formingthe components of the carrying devices and the like need to be bothrustproof and explosion-proof and it is difficult to select suchmaterials.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide asubstrate processing apparatus capable of avoiding the exertion of badinfluences of a substrate-processing atmosphere produced by a processingmedium supply means on a processed substrate while the processed waferis in a waiting state, and of preventing the contamination of theprocessing medium supply means with an atmosphere of the processingliquid or an atmosphere produced by other processing medium supplymeans.

Another object of the present invention is to provide a substrateprocessing apparatus capable of effectively controlling asubstrate-processing atmosphere of a processing liquid in one unit.

With the foregoing objectives in view, the present invention provides asubstrate processing apparatus, which includes: a substrate supportmember that supports a substrate; an enclosure structure enclosing thesubstrate support member, defining a processing space, and provided withopenings; a shutter adapted to be operated to close and open theopenings of the enclosure structure; and a processing fluid supply unitarranged outside the enclosure structure, and provided with a supplyport through which a processing fluid for processing a substrate issupplied onto the substrate supported by the substrate support member,wherein at least a part of the processing fluid supply unit includingthe supply port is advanced through the opening of the enclosurestructure into the processing space when the supply unit feeds theprocessing fluid onto the substrate.

The apparatus may further include a cup disposed in the processing spaceand surrounding the substrate support member.

The apparatus may further include a top-plate adapted to move, relativeto the substrate supported by the substrate support member, between afirst position where the top-plate is close to an upper face of thesubstrate supported by the substrate support member and a secondposition where the top-plate is remote from the upper face of thesubstrate supported by the substrate support member.

The apparatus may further include an under-plate adapted to move,relative to the substrate supported by the substrate support member,between a first position where the under-plate is close to a lower faceof the substrate supported by the substrate support member and a secondposition where the under-plate is remote from the lower face of thesubstrate supported by the substrate support member.

The apparatus may further include a second enclosure structure enclosingthe first enclosure structure and defining a space between the first andsecond enclosure structures.

According to the second aspect of the present invention, there isfurther provided a substrate processing apparatus, which includes: asubstrate support member that supports a substrate arranged in aprocessing space; a first processing fluid supply unit that supplies aprocessing fluid onto a substrate supported by the substrate supportmember; a second processing fluid supply unit that supplies a processingfluid onto a substrate supported by the substrate support member; afirst housing defining a first room separated from the processing spacein which the substrate support member is arranged, the first room beingadapted to accommodate the first processing fluid supply unit; and asecond housing defining a second room separated from the first room andfrom the processing space in which the substrate support member isarranged, the second room being adapted to accommodate the secondprocessing fluid supply unit.

The apparatus may further include an enclosure structure defining theprocessing space in which the substrate support member is arranged.

The apparatus may further include two cleaning units disposed in thefirst room and the second room, respectively.

In a specific embodiment, the first processing fluid supply unitsupplies a chemical liquid, and the second processing fluid supply unitsupplies a rinse liquid.

According to the third aspect of the present invention, there is furtherprovided a substrate processing apparatus, which includes: a substratesupport member that supports a substrate; a first enclosure structureenclosing the substrate support member, defining a processing space, andprovided with an opening; a first shutter adapted to be operated to openand close the opening of the first enclosure structure; a secondenclosure structure enclosing the first enclosure structure, defining aspace between the first and second enclosure structures, and providedwith an opening; and a second shutter adapted to be operated to open andclose the opening of the second enclosure structure.

The apparatus may further include a top-plate adapted to move, relativeto the substrate supported by the substrate support member, between afirst position where the top-plate is close to an upper face of thesubstrate supported by the substrate support member and a secondposition where the top-plate is remote from the upper face of thesubstrate supported by the substrate support member.

The apparatus may further include an inert gas supplying means thatsupplies inert gas into an area above the top-plate in the processingspace.

In a specific embodiment, the top-plate is rotatable.

According to the fourth aspect of the present invention, there isfurther provided a substrate processing apparatus, which includes: asubstrate support member that supports a substrate; an enclosurestructure enclosing the substrate support member, defining a processingspace, and provided with an opening; a top-plate adapted to move,relative to the substrate supported by the substrate support member,between a first position where the top-plate is close to an upper faceof the substrate supported by the substrate support member and a secondposition where the top-plate is remote from the upper face of thesubstrate supported by the substrate support member; and an inert gassupply means that supplies inert gas into an area above the top-plate inthe processing space.

In a specific embodiment, the top-plate is rotatable.

The apparatus may further include an exhaust mechanism that dischargesan atmosphere of the processing space.

The apparatus may further include a cup arranged in the processing spaceand surrounding the substrate support member.

In a specific embodiment, the cup and the substrate support membercapable of relative movement.

The apparatus may further include an exhaust mechanism that dischargesan atmosphere of a space surrounded by the cup.

The apparatus may further include an under-plate adapted to move,relative to the substrate supported by the substrate support member,between a first position where the under-plate is close to a lower faceof the substrate supported by the substrate support member and a secondposition where the under-plate is remote from the lower face of thesubstrate supported by the substrate support member.

The apparatus may further include a temperature regulator that controlstemperature of the inert gas to be supplied by the inert gas supplymeans.

The apparatus may further include a processing fluid supply unit forsupplying a processing fluid onto a substrate supported on the substratesupport member. In this case, the temperature regulator controls thetemperature of the inert gas so that, when temperature of the processingfluid is higher than a room temperature, the temperature of the inertgas is equal to or higher than the temperature of the processing fluid,and when the temperature of the processing fluid is lower than a roomtemperature, the temperature of the inert gas is equal to or lower thanthe temperature the processing fluid.

In the following description of the present invention, a substrate is,for example, a semiconductor wafer or a glass substrate for LCDs. Thesubstrate may be a CD substrate, a printed wiring board or a ceramicsubstrate. A processing fluid is a processing liquid or a processinggas. Possible processing fluids include cleaning liquids, such asvarious chemical solutions and pure water, processing liquids fortreating wafers by various processes, and processing gases for treatingwafers by various processes. The substrate processing apparatus isembodied in a substrate cleaning system that carries out a cleaningprocess for cleaning, for example, wafers with a cleaning liquid.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objectives, features and advantages of the presentinvention will become more apparent from the following description takenin connection with the accompanying drawings, in which:

FIG. 1 is a plan view of a cleaning system;

FIG. 2 is a side elevation of the cleaning system shown in FIG. 1;

FIG. 3 is a sectional view of the cleaning system shown in FIG. 1,schematically showing the arrangement of a wafer transfer unit, a mainwafer-carrying unit, a heating unit and a cooling unit;

FIG. 4 is a plan view of a substrate-cleaning unit in a preferredembodiment according to the present invention;

FIG. 5 is a sectional view of the substrate-cleaning unit shown in FIG.4;

FIG. 6 is a sectional view of an under-plate and an under-shaft;

FIG. 7 is a plan view of the under-plate shown in FIG. 6;

FIG. 8 is an enlarged longitudinal sectional view of an upper part of anouter chamber;

FIG. 9 is a schematic sectional view of assistance in explaining adraining process for draining liquid drops from an inner cup into a misttrap;

FIG. 10 is a schematic sectional view of assistance in explaining adraining process for draining liquid drops from the outer chamber into amist trap;

FIG. 11 is diagrammatic view of an IPA circulation unit and a processingliquid circulation unit;

FIG. 12 is a longitudinal sectional view of assistance in explaining awetting process for wetting both the surfaces of a wafer with a chemicalsolution;

FIG. 13 is a longitudinal sectional view of assistance in explaining acleaning process for cleaning both the surfaces of a wafer with achemical solution;

FIG. 14 is a longitudinal sectional view of assistance in explaining agas supply process for supplying N₂ gas onto both the surfaces of awafer;

FIG. 15 is a longitudinal sectional view of assistance in explaining asubstrate-cleaning unit in a preferred embodiment according to thepresent invention provided with a fan-and-filter unit (FFU) and anexhaust system;

FIG. 16 is a view of an outer vessel and an inner cup respectivelyprovided with straightening plates on their inner surface;

FIG. 17 is a view of an outer vessel and an inner cup respectivelyprovided with straightening plates on their inner surface;

FIG. 18 is a sectional view of an under-plate and an under-shaft inmodifications; and

FIG. 19 is a plan view of an under-plate in another modification.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A substrate cleaning unit for cleaning both the surfaces of a wafer W,i.e., a substrate, will be described as a preferred embodiment of asubstrate processing apparatus according to the present invention. FIGS.1 and 2 are a plan view and a side elevation, respectively, of acleaning system 1 provided with substrate cleaning units 12, 13, 14 and15. The cleaning system 1 includes a processing section 2 for cleaning awafer W by a wafer-cleaning process and heating the wafer W by a thermalprocess, a delivery section 3 for carrying the wafer W to and carryingthe same away from the processing section 2.

The delivery section 3 has a carrier delivery port 4 and awafer-carrying part 5. The carrier delivery port 4 has a table 6. Acarrier C holding, for example, twenty-five wafers W at intervals in ahorizontal position is placed on the table 6. The wafer-carrying part 5is provided with a wafer transfer mechanism 7 for transferring wafersbetween the carrier C placed on the table 6 and the processing section2.

The carrier C has an opening formed in one side thereof and closed by alid. Wafers W are put into and taken out of the carrier C through theopening. Ledges for supporting wafers W thereon are attached to theinner side surfaces of the carrier C so as to form twenty-five slots foraccommodating wafers W at predetermined intervals. Each wafer W isinserted in the slot with its surface on which semiconductor devices areto be formed facing up.

Three carriers C, for instance, can be mounted on the surface of thetable 6 of the carrier delivery port 4 in a horizontal, lineararrangement in a Y-direction, with their sides provided with the lidsfacing a partition wall 8 separating the carrier delivery port 4 and thewafer-carrying part 5. The partition wall 8 is provided with windows 9in parts thereof respectively corresponding to positions where thecarriers C are located. A window closing mechanism 10 is disposed on theside of the wafer-carrying part 5 of each window 9.

The window closing mechanism 10 is provided with a shutter or the likefor closing the window 9. The window closing mechanism 10 is capable ofoperating the shutter to open and close the window 9 and of operatingthe lid to open and close the carrier C. Preferably, the operation ofthe window closing mechanism 10 is inhibited by an interlockingmechanism while any carrier C is not located at the predeterminedposition. The window 9 is opened and the lid of the carrier C is removedto open the carrier C into the wafer-carrying device 5. Then the wafertransfer mechanism 7 of the wafer-carrying part 5 is able to access thecarrier C and able to carry a wafer W. A wafer detector, not shown, isdisposed in an upper part of the window 9 to detect the number of wafersW contained in the carrier C and the state of each wafer W in each slot.The wafer detector may be included in the window closing mechanism 10.

The wafer transfer mechanism 7 of the wafer-carrying part 5 is capableof moving in the Y-direction and a Z-direction and of turning in an X-Yplane (θ-direction). The wafer transfer mechanism 7 has a wafer-handlingarm 11 capable of gripping and carrying a wafer W and of moving in anX-direction. The wafer transfer mechanism 7 is capable of accessing theslot at any height of any one of the carriers C located on the table 6and of accessing either the wafer transfer device 16 or 17 disposed in avertical arrangement in the processing section 2 to transfer a wafer Wfrom the carrier delivery port 4 to the processing section 2 or from theprocessing section 2 to the carrier delivery port 4.

The processing section 2 has a main wafer-carrying mechanism 18, the twowafer transfer devices 16 and 17, the four substrate cleaning units 12,13, 14 and 15, three heating units 19, 20 and 21 for heating and dryingwafers W, and a cooling unit 22 for cooling heated wafers W. The mainwafer-carrying mechanism 18 is capable of accessing the wafer transferunits 16 and 17, the substrate cleaning units 12, 13, 14 and 15, theheating units 19, 20 and 21 and the cooling unit 22. A wafer W is heldtemporarily in the wafer transfer unit 16 or 17 before the wafer W istransferred from the wafer-carrying part 5 to the processing section 2or from the processing section 2 to the wafer-carrying device 5.

The processing section 2 includes a power unit 23 for supplying power tothe cleaning system 1, a machine control unit 24 for controlling theoperations of the component devices of the cleaning system 1 and thegeneral operations of the cleaning system 1, and a processing liquidstorage unit 25 for storing a predetermined cleaning liquid to thesubstrate cleaning units 12, 13, 14 and 15. The power unit 23 isconnected to a main power source, not shown. A fan-and-filter unit (FFU)26 for supplying clean air to the foregoing units and the mainwafer-carrying mechanism 18 is installed on the ceiling of theprocessing section 2.

The power unit 23, the processing liquid storage unit 25 and the machinecontrol unit 24 may be disposed outside the processing section 2, or theunits 23, 24 and 25 may be installed in the processing section 2 so thatthe same can be pulled out of the processing section 2. This facilitatesthe maintenance of the wafer transfer units 16 and 17, the mainwaver-carrying mechanism 18, the heating units 19, 20 and 21, and thecooling unit 22.

FIG. 3 is a schematic sectional view of assistance in explaining thearrangement of the wafer transfer units 16 and 17, the main wafercarrying mechanism 18 adjacent to the wafer transfer units 16 and 17with respect to the X-direction, the heating units 19, 20 and 21, andthe cooling unit 22. The wafer transfer units 16 and 17 are disposed ina vertical arrangement. The lower wafer transfer unit 17 is used totransfer a wafer W from the carrier delivery port 4 to the processingsection 2. The upper wafer transfer unit 16 is used for transferring awafer W from the processing section 2 to the carrier delivery port 4.

Part of air supplied by the FFU 26 flows through the wafer transferunits 16 and 17 and a space over the wafer transfer units 16 and 17 intothe waver-carrying device 5. Thereby, the flow of particles from thewafer-carrying part 5 into the processing section 2 can be prevented tomaintain the processing section 2 in a satisfactory cleanliness.

The main wafer-carrying mechanism 18 has a cylindrical support member 30having vertical walls 27 and 28 and a side opening 29 formed between thevertical walls 27 and 28, and a wafer carrier 31 placed in thecylindrical support member 30 for vertical movement. The cylindricalsupport member 30 can be driven for turning by a motor 32 together withthe wafer carrier 31. The wafer carrier 31 has a carrying base 33, andthree carrying arms 34, 35 and 36 capable of moving along the base 33.The carrying arms 34, 35 and 36 are formed in sizes such that thecarrying arms 34, 35 and 36 are able to move through the side opening29. The carrying arms 34, 35 and 36 are moved individually for forwardand backward movement by a driving mechanism including a motor built inthe carrying base 33, and a belt mechanism. The wafer carrier 31 isdriven by a motor 37 through a belt 38 extended between a drive pulley39 and a driven pulley 40 for vertical movement.

The three heating units 19, 20 and 21 are stacked on the cooling unit 22for the forced cooling of a wafer W. The heating units 19, 20 and 21 andthe cooling unit 22 may be installed in the space over the wafertransfer units 16 and 17. When the heating units 19, 20 and 21 and thecooling unit 22 are installed in the space over the wafer transfer units16 and 17, a space occupied by the heating units 19, 20 and 21 and thecooling unit 22 shown in FIG. 1 can be used as a utility space.

The substrate cleaning units 12, 13, 14 and 15 are stacked in two layerseach for two of them. As shown in FIG. 1, the substrate cleaning units12 and 14 have symmetrical structure with respect to a wall 41separating the units 12 and 14 from each other. The substrate cleaningunits 13 and 15 have symmetrical structure with respect to a wall 41separating the units 13 and 15 from each other. The substrate cleaningunits 12, 13, 14 and 15 are substantially the same in construction,except that the substrate cleaning units 12 and 14 are symmetrical andthe substrate cleaning units 13 and 15 are symmetrical. Therefore, theconstruction of only the substrate cleaning unit 12 will be described byway of example.

Referring to FIG. 4 showing the substrate-cleaning unit 12 in a planview, installed in a space defined by a unit casing 42 is a chambercasing 43 defining a processing chamber 43A, a chemical liquid supplyarm housing 44 defining a storage chamber for chemical liquid supply arm50, and a rinsing-and-drying arm housing 45 defining a storage chamberfor rinsing-and-drying arm 55. The unit casing 42 is provided with anopening 46′ covered with a mechanical shutter 46 operated by a shutteroperating mechanism, not shown. When carrying a wafer W by the carryingarm through the opening 46′ into the substrate-cleaning unit 12, themechanical shutter 46 is opened. The mechanical shutter 46 is on theinner side of the opening 46′ so that an atmosphere in the unit casing42 may not leak outside even if the interior space of the unit casing 42is at a positive pressure.

The chamber casing 43 is provided with an opening 47′. The opening 47′is covered with a shutter 47 for the chamber casing 43 operated by acylinder actuator, not shown. When carrying a wafer W by the carryingarm 34 through the opening 47′ into the processing chamber 43A, theshutter 47 is opened. Both the mechanical shutter 46 for the unit casing42 and the shutter 47 for the chamber casing 43 may be operated by oneand the same shutter operating mechanism. The shutter 47 is on the innerside of the opening 47′ so that an atmosphere in the chamber casing 43may not leak outside even if the interior space of the chamber casing 43is at a positive pressure. The chamber casing 43 is provided with anopening 48′. The opening 48′ is covered with a shutter 48 for closingthe processing liquid supply arm storage chamber defined by the chemicalliquid supply arm housing 44. The shutter 48 is operated by a shutteroperating mechanism, not shown. When isolating the chemical liquidsupply arm housing 44 from the processing chamber 43A, the shutter 48 isclosed. The chamber casing 43 is provided with an opening 49′. Theopening 49′ is covered with a shutter 49 for closing therinsing-and-drying arm storage chamber defined by the rinsing-and-dryingarm housing 45. The shutter 49 is operated by a shutter operatingmechanism, not shown. When isolating the interior of therinsing-and-drying arm housing 45 from the processing chamber 43A, theshutter 49 is closed.

A chemical liquid supply arm 50 is housed in the chemical liquid supplyarm housing 44. The arm 50 has two spouting systems, one for spouting achemical liquid and N₂ gas, the other for spouting IPA and pure water.The arm 50 can be moved into the processing chamber 43A and can be movedso as to sweep the surface of a wafer W supported on a spin chuck 59from the center to the periphery of the wafer W. The chemical liquidsupply arm 50 is retracted into the chemical liquid supply arm housing44 when the same is not in use for processing. Since an atmosphere ofthe processing liquid prevails always in the chemical liquid supply armhousing 44, the component parts of the chemical liquid supply arm 50 andthe chemical liquid supply arm housing 44 are formed ofcorrosion-resistant materials. The arm 50 is provided with a chemicalliquid pouring nozzle 51 and a rinsing liquid pouring nozzle 52. Thechemical liquid and N₂ gas is poured through the chemical liquid pouringnozzle 51, and IPA and pure water is poured through the rinsing liquidpouring nozzle 52. The chemical liquid supply arm 50 may be furtherprovided with a chemical liquid supply nozzle for pouring a secondchemical liquid. The shutter 48 is opened to admit the arm 50 into theprocessing chamber 43A.

A rinsing-and-drying arm 53 housed in the rinsing-and-drying arm housing45. The arm 53 has two spouting systems, one for spouting N₂ gas, theother for spouting IPA and pure water. The arm 53 turns to be moved intothe processing chamber 43A and turns to be moved so as to sweep thesurface of a wafer W supported on the spin chuck 59 from the center tothe periphery of the wafer W. The arm 53 is retracted into the housing45 when the same is not in use for processing. Although any atmosphereof a processing liquid does not prevail in the housing 45, the componentparts of the arm 53 and the housing 45 may be formed ofcorrosion-resistant materials. The arm 53 is provided with a N₂ gasspouting nozzle 54 and a rinsing liquid pouring nozzle 55. N₂ gas isspouted through the N₂ gas spouting nozzle 54, and IPA and pure water ispoured through the rinsing nozzle 55. The shutter 49 forrinsing-and-drying arm housing 45 is opened to admit therinsing-and-drying arm 53 into the processing chamber 43A through theopening 49′.

A cleaning device 56 for cleaning the chemical liquid supply arm 50 isdisposed in the chemical liquid supply arm housing 44 to clean the arm50 when necessary. When cleaning the arm 50, the shutter 48 is closed toprevent the leakage of a cleaning atmosphere from the interior of thehousing 44 into interior of the unit casing 42 and into the processingchamber 43A. A cleaning device 57 for cleaning the rinsing-and-dryingarm 53 is disposed in the rinsing-and-drying arm housing 45 to clean thearm 53 when necessary. When cleaning the rinsing-and-drying arm 53, theshutter 49 is closed to prevent the leakage of a cleaning liquidatmosphere from the interior of the housing 45 into interior of the unitcasing 42 and into the processing chamber 43A.

Referring to FIG. 5, arranged in the chamber casing 43 are a cup 58 forsurrounding a wafer W, a spin chuck 59 (i.e., a wafer support means) forsupporting a wafer W with a surface thereof to be processed faced up,and a top-plate 60 capable of vertically moving relative to the uppersurface of a wafer W supported by the spin chuck 59. The chamber casing43 has a taper wall 43′ at a level corresponding to a wafer W supportedon the spin chuck 59. The taper wall 43′ surrounds a wafer W supportedon the spin chuck 59. The shutter 47 of the chamber casing 43 serves asa part of the taper wall 43′. When mounting a wafer W on the spin chuck59 and removing the same from the spin chuck 59, the wafer W needs onlyto be moved horizontally after opening the shutter 47.

The spin chuck 59 has a chuck body 61 for supporting a wafer W thereon,and a rotating tubular shaft 62 connected to the bottom of the chuckbody 61. An under-plate 63 is disposed inside the chuck body 61. Theunder-plate 63 is movable relative to the bottom of a wafer W supportedon the spin chuck 59.

A plurality of support pins, not shown and a plurality of holdingmembers 64 are connected to an upper part of the chuck body 61 tosupport and hold a wafer W at a plurality of parts thereof. A belt 65 isextended between the rotating tubular shaft 62 and a drive pulleymounted on the output shaft of a motor 66 to drive the spin chuck 59 forrotation by the motor 66. Each holding member 64 is provided with aweight that is moved by a centrifugal force when the spin chuck 59 isrotated to causes an upper part of the holding member 64 to moveradially inward and to engage a peripheral part of the wafer W. Thewafer W is supported on the support pins while the spin chuck 59 is at astandstill, and is held by the holding members 64 while the spin chuck59 is rotating.

The under-plate 63 is connected to the upper end of an under-plate shaft67 extending through the rotating tubular shaft 62, and the lower end ofthe under-plate shaft 67 is connected to the upper surface of ahorizontal plate 68. The horizontal plate 68 thus supporting theunder-plate shaft 67 is moved vertically by a lifting mechanism 69, suchas a pneumatic cylinder actuator. Thus, the under-plate 63 can bevertically moved between a lower waiting position in a lower part of thechuck body 61 as shown in FIG. 5, and a working position in an upperpart of the chuck body 61 as shown in FIG. 13. The under-plate 63 isheld at the working position while the lower surface of a wafer Wsupported on the spin chuck 59 is subjected to a cleaning process asshown in FIG. 13. The under-plate 63 may be fixedly held at apredetermined level, and the spin chuck 59 may be moved vertically by alifting mechanism, not shown, connected to the rotating tubular shaft 62to move the under-plate 63 between a waiting position and a workingposition relative to the spin chuck 59.

The top-plate 60 is connected to the lower end of a top-plate shaft 70,and is rotated by a motor 72 mounted on a horizontal plate 71. Thetop-plate shaft 70 is supported for rotation by the horizontal plate 71so as to extend vertically downward. A lifting mechanism 73, such as apneumatic cylinder actuator, fixedly mounted on the upper wall of thechamber casing 43 moves the horizontal plate 71 vertically to move thetop-plate 60 vertically between a waiting position and a workingposition. When the top-plate 60 is in the waiting position, thetop-plate 60 is apart from the upper surface of a wafer W supported onthe spin chuck 59 as shown in FIG. 5. When the top-plate 60 is in theworking position, the top-plate 60 is close to the upper surface of thewafer W as shown in FIG. 13. The top-plate 60 is held at the workingposition while the upper surface of the wafer W is subjected to acleaning process.

The cup 58 is vertically movable between a retracted position shown inFIG. 5 (i.e., a lower position) and a working position (i.e., an upperposition) shown in FIG. 13. When the cup 58 is in the retractedposition, an upper part of the spin chuck 59 protrudes upward beyond theupper end of the cup 58 so that a wafer can be transferred to or removedfrom the spin chuck 59. When the cup 58 is in the working position, thecup 58 surrounds the spin chuck 59 and a wafer W supported on the spinchuck 59 to prevent the processing liquid supplied onto the wafer fromscattering.

When the cup 58 is lowered to the retracted position shown in FIG. 5 anda wafer W is transferred to or removed from the spin chuck 59, thetop-plate 60 and the under-plate 63 are held at their waiting positions,respectively, to form a sufficiently wide gap between the under-plate 63and the wafer W supported on the spin chuck 59, and to form asufficiently wide gap between the top-plate 60 and the wafer W supportedon the spin chuck 59. Thus, the wafer W can be smoothly transferred toor removed from the spin chuck 59.

Referring to FIG. 6, a fluid passage 75 is extended through theunder-plate 63 and the under-plate shaft 67. A cleaning liquid, such asa chemical liquid or pure water, or a drying gas is supplied through thefluid passage 75. As shown in FIG. 7, peripheral nozzle holes 76 to 79are formed in four peripheral parts of the under-plate 63, and a centralnozzle hole 80 is formed in a central part of the under-plate 63. Achemical liquid, IPA, pure water and N₂ can be spouted through thenozzle holes 76 to 80. The peripheral nozzle holes 76 to 79 are inclinedradially outward.

As shown in FIG. 8, a fluid passage 85 is extended through the top-plate60 and the top-plate shaft 70. Pure water or a drying gas is suppliedthrough the fluid passage 85. A N₂ gas supply port 86 is formed in thetop wall of the chamber casing 43. N₂ gas is supplied through the N₂ gassupply port 86 into a space between the top wall of the chamber casing43 and the top-plate 60.

Referring to FIG. 9, a cup drain pipe 87 is connected to the bottom wallof the cup 58 to drain a liquid collected in the cup 58. The cup drainpipe 87 is vertically movable through an opening 88 formed in the bottomwall of the chamber casing 43. A lower end part of the cup drain pipe 87is inserted in a cup mist trap 89. The cup mist trap 89 removes gases,which are typically in the form of gas babbles existing in a liquid,from the liquid drained from the cup 58. The gases removed from theliquid are discharged outside through an exhaust pipe 90 connected tothe cup mist trap 89. The liquid eliminated of the gases is recoveredthrough a cup drain line 92 connected to the cup mist trap 89.

A casing drain pipe 93 is connected to the bottom wall of the chambercasing 43 to drain a liquid collected in the processing chamber 43A. Thecasing drain pipe 93 is connected to a casing mist trap 94. The misttrap removes gases, which are typically in the form of gas babblesexisting in a liquid, from the liquid drained from the processingchamber 43A. The gases removed from the liquid are discharged outsidethrough an exhaust pipe 95 connected to the casing mist trap 94. Theliquid eliminated of the gases is recovered through a casing drain line96 connected to the casing mist trap 94.

When the cup 58 is lowered to its lower position as shown in FIG. 10,the spin chuck 59 and a wafer W supported on the spin chuck 59 arepositioned above the upper end of the cup 58. When the cup 58 is set atthe lower position, liquid drops contained in the processing chamber 43Aflow down in a space surrounding the cup 58 and are drained through thecasing drain pipe 93. The cup 58 surrounds the spin chuck 59 and thewafer supported on the spin chuck 59 to prevent the cleaning liquid orthe like supplied onto both the surfaces of the wafer W and splashed bythe wafer W from spreading in the casing 43 when the cup 58 is raised toits upper position as shown in FIG. 12. When the cup 58 is set at theupper position, liquid drops scattered in the space surrounded by thecup 58 are drained through the cup drain pipe 87.

FIG. 11 is diagrammatic view of an IPA circulation unit 112 and aprocessing liquid circulation unit 100. The cup drain line 92 connectedto the cup mist trap 89 can be connected to either a drain pipe 98 or achemical liquid recovery line 99 by a selector valve 97. The chemicalliquid recovery line 99 is connected to a tank 101 included in thechemical liquid circulation unit 100. A drain pipe 102 and a chemicalliquid circulation line 103 are connected to the tank 101. The chemicalliquid circulation line 103 is provided with a pump 104 and a filter105. The chemical liquid circulation line 103 is connected to a chemicalliquid supply line 106. The chemical liquid supply line 106 is connectedto the chemical liquid supply nozzle 51 and the fluid passage 75. Thechemical liquid supply line 106 is provided with a temperature regulator108 that regulates the temperature of the chemical liquid with, forexample, a heater 107. The temperature of the chemical liquid to besupplied onto the wafer W is regulated. The chemical liquid recovered bythe chemical liquid circulation unit 100 is reused.

The casing drain line 96 connected to the casing mist trap 94 can beconnected to either a drain pipe 110 or an IPA recovery line 111 by aselector valve 109. The IPA recovery line 111 is connected to a tank 113included in the IPA circulation unit 112. A drain pipe 114 and an IPAcirculation line 115 are connected to the tank 113. The IPA circulationline 115 is provided with a pump 116 and a filter 117. The IPAcirculation line 115 can be selectively connected to the rinsing liquidpouring nozzle 52, the rinsing liquid pouring nozzle 55 or the fluidpassage 75 by a selector valve 118. IPA recovered by the IPA circulationunit 112 is reused. The selector valve 118 selects either unused IPA(pur) supplied through an IPA supply line 120 or recovered IPA (rec)recovered by the IPA circulation unit 112. The unused IPA (pur) suppliedthrough the IPA supply line 120 is delivered to the rinsing liquidpouring nozzle 55, and the recovered IPA (rec) recovered by the IPAcirculation unit 112 is supplied to the rinsing liquid pouring nozzle52. Either the unused IPA (pur) supplied through the IPA supply line 120or the recovered IPA (rec) recovered by the IPA circulation unit 112 canbe supplied to the fluid passage 75.

The other substrate cleaning units 13, 14 and 15 of the cleaning system1 are similar in construction to the substrate cleaning unit 12, and arecapable of simultaneously cleaning both the surfaces of a wafer W with acleaning liquid.

In the cleaning system 1, a carrier C holding twenty-five untreatedwafers W is carried onto the table 6 of the carrier delivery port 4 by acarrying robot, not shown. The wafer-handling arm 11 takes the wafers Wone at a time from the carrier C and transfers the wafer W to the wafertransfer units 16 and 17. The carrying arm 34 carries the wafer W to thesubstrate cleaning unit 12, 13, 14 or 15. Then, the wafer W is cleanedby a predetermined cleaning process to remove contaminants includingparticles. After the wafer W has been cleaned by the cleaning process,the wafer transfer mechanism takes out the cleaned wafer W from thesubstrate-cleaning unit 12, 13, 14 or 15 and transfers the same to thewafer-handling arm 11. Then, the wafer-handling arm 11 put the cleanedwafer W in a carrier C.

The operation of the substrate-cleaning unit 12 for carrying out thecleaning process will be described by way of example. Referring to FIG.5, the mechanical shutter 46 of the unit casing 42 of the substratecleaning unit 12 and the shutter 47 of the chamber casing 43 are opened,and then the carrying arm 34 holding a wafer W is advanced into thechamber 43A of the substrate cleaning unit 12 through the openings 46′and 47′. The cup 58 is held at the lower position to expose an upperpart of the chuck body 61. As shown in FIG. 5, the under-plate 63 islowered to the waiting position in side the chuck body 61. The top-plate60 is raised to the waiting position before hand. The second shutter 48for covering the opening 48′ and the third shutter 49 for covering theopening 49′ are closed.

The main wafer-carrying mechanism 18 moves the carrying arm 34 down, andtransfers the wafer W to the holding members 64. The spin chuck 59supports the wafer W on the support pins, not shown, with a surface ofthe wafer W provided with semiconductor devices faced up. Since theunder-plate 63 is held at the waiting position and is spaced asufficient distance apart from the wafer W supported on the spin chuck59, a sufficiently large space can be secured for the movement of thecarrying arm 34 to transfer the wafer W to the spin chuck 59. Aftertransferring the wafer W to the spin chuck 59, the carrying arm 34 isretraced from the chamber casing 43 and the unit casing 42 through theopening 46′ and 47. Then, the mechanical shutter 46 of the unit casing42 of the substrate cleaning unit 12 and the shutter 47 of the chambercasing 43 are closed. In addition, the cup 58 is raised to surround thechuck body 61 and the wafer W.

Subsequently, the under-plate 63 is raised to the working position inthe chuck body 61. As shown in FIG. 12, a gap L₁ of a thickness in therange of, for example, about 0.5 to about 3 mm is formed between theunder-plate 63 set at the working position and the lower surface (backsurface) of the wafer W supported on the spin chuck 59. The chemicalliquid is supplied through the fluid passage 75 into the gap L₁ betweenthe under-plate 63 and the lower surface of the wafer W. The temperatureregulator 108 regulates the temperature of the chemical liquid at apredetermined temperature. The chemical liquid is exuded graduallythrough the fluid passage 75 into the gap L₁. Then, the chemical liquidspreads over the entire lower surface of the wafer W in the narrow gapL₁ and forms a chemical liquid film uniformly wetting the lower surfaceof the wafer W. After the chemical liquid film has been formed in thewhole gap L₁, the supply of the chemical liquid through the fluidpassage 75 is stopped and the lower surface of the wafer W is cleaned.The breakage of the chemical liquid film formed in the gap L₁ can beprevented by the surface tension of the chemical liquid. If the chemicalliquid film should break, some parts of the lower surface of the wafer Wcannot be wetted with the chemical liquid or bubbles form in thechemical liquid film to cause faulty cleaning. Since the chemical liquidfilm is formed in the narrow gap L₁ between the under-plate 63 and thelower surface of the wafer W, the chemical liquid film is able to retainits shape and hence faulty cleaning can be avoided. The spin chuck 59holding the wafer W is rotated at a comparatively low speed in the rangeof, for example, 10 to 30 rpm that will not break the chemical liquidfilm. Consequently, the chemical liquid forming the chemical liquid filmflows, which prevents the stagnation of the chemical liquid in thechemical liquid film and enhances cleaning efficiency. The spin chuck 59holding the wafer W may be turned intermittently; for example, therotation of the spin chuck 59 for a predetermined period and thestandstill of the same for a predetermined period may be repeatedalternately. Such intermittent rotation of the spin chuck 59 holding thewafer W facilitates the spread of the chemical liquid over the lowersurface of the wafer W. Naturally, the wafer W may be kept stoppedduring the cleaning process. The chemical liquid does not need to besupplied after the chemical liquid film has been formed because theentire lower surface of the wafer W can be cleaned with the chemicalliquid forming the chemical liquid film as long as the chemical liquidfilm does not break. If the chemical liquid film is going to break, thechemical liquid is supplied additionally to repair the chemical liquidfilm. Thus, the chemical liquid is economized to reduce the consumptionof the chemical liquid. The wafer W may be rotated to make the chemicalliquid forming the chemical liquid film drip from the periphery of theunder-plate 63 and the chemical liquid may be continuously suppliedthrough the fluid passage 75 into the gap L₁ to supply the new chemicalliquid into the chemical liquid film to achieve the cleaning processsatisfactorily. In such a case, it is preferable to supply the newchemical liquid slowly so that the chemical liquid may be economized.

In the meantime, the shutter 48 of the chemical liquid supply armhousing 44 is opened, the chemical liquid supply arm 50 is turned to aposition above the wafer W. The chemical liquid supply arm 50 sweeps theupper surface of the wafer W supported on the spin chuck 59 at leastfrom the center to the periphery of the wafer W and pours the chemicalliquid onto the wafer W. The temperature of the chemical liquid isregulated at a predetermined temperature by the temperature regulator108. The spin chuck 59 holding the wafer W is rotated to form a chemicalliquid film uniformly over the upper surface of the wafer W. In thisstate, the shutter 49 is closed to keep the rinsing-and-drying armhousing 45 closed so that the rinsing-and-drying arm 53 may not becontaminated with the chemical liquid. After a chemical liquid film hasbeen formed over the upper surface of the wafer W, the chemical liquidsupply arm 50 is retracted into the chemical liquid supply arm housing44, and the second shutter 48 is closed. The top-plate 60 is moved closeto the upper surface of the wafer W such that the top-plate does notcome into contact with the chemical liquid film formed over the uppersurface of the wafer W. For example, a gap L₂ is formed between theupper surface of the wafer W held by the spin chuck 59 and the top-plate60 located close to upper surface of the wafer W. The top-plate suppliesthe chemical liquid onto the wafer W to repair the chemical liquid film,when chemical liquid film is going to break. The upper surface of thewafer W is cleaned mainly with the chemical liquid having beenpreviously supplied by the chemical liquid supply arm 50. After thechemical liquid film has been formed, further supply of the new chemicalliquid is restrained to economize the chemical liquid. The wafer W maybe rotated to make the chemical liquid forming the chemical liquid filmdrip from the periphery of the wafer W and the chemical liquid may becontinuously supplied from the top-plate 60 to supply the new chemicalliquid into the chemical liquid film to achieve the cleaning processsatisfactorily. The evaporation of the chemical liquid forming thechemical liquid film is suppressed by the top-plate 60 covering thewafer W. The top-plate 60 may touch the chemical liquid film to ensurethat the chemical liquid film is formed between the top-plate 60 and theupper surface of the wafer W.

N₂ gas is supplied into a space over the tip plate 60 through the N₂ gassupply port 86 formed in the top wall of the chamber casing 43 toproduce a N₂ gas downflow. The N₂ gas filling up the space between theupper surface of the top-plate 60 and the top wall of the chamber casing43 prevents the vapor of the chemical liquid and rising around thetop-plate 60 from flowing into the space extending over the top-plate60. Thus, the remaining of the chemical liquid in an upper region of theprocessing chamber 43A defined by the chamber casing 43 after thecompletion of the cleaning process can be avoided and water marks arehardly formable.

As shown in FIG. 11, N₂ gas heated at a predetermined temperature by atemperature regulator 150 may be supplied through the N₂ gas supply port86 during the cleaning process. Preferably, the N₂ gas is hated at atemperature such that the atmosphere in the processing chamber 43A inthe chamber casing 43 is substantially equal to the temperature of theprocessing liquid supplied onto the wafer W. It is preferable that thetemperature of the N₂ gas is controlled so that it is equal to orslightly higher than that of the chemical liquid when the temperature ofthe chemical liquid is higher than the room temperature, and so that thetemperature of the N₂ gas is equal to or slightly lower than that of thechemical liquid when the temperature of the chemical liquid is lowerthan the room temperature. The N₂ gas of the thus regulated temperaturehas an effect of reducing difference in the processing effect of theprocessing liquid between wafers, in addition to an effect of preventingthe diffusion of the atmosphere of the chemical liquid. When thechemical liquid is an etchant (etching liquid), the etchant is able toetch wafers at the same etch rate. Moreover, the intra-surfaceuniformity of the processing effect of the chemical liquid in each waferW can be improved.

After the completion of processing both the surfaces of the wafer W withthe chemical liquid, the top-plate 60 is raised while the same isrotated. The top-plate 60 is rotated to force the chemical liquidwetting the top-plate 60 to fall off the top-plate 60. The chemicalliquid thus removed from the top-plate 60 is drained through the cupdrain pipe 87. After the top-plate 60 has been moved to the waitingposition, the spin chuck is rotated at, for example, 2000 rpm forseconds to force the chemical liquid wetting the wafer W to fall off thewafer W. The chemical liquid thus removed from the wafer W is drainedthrough the cup drain pipe 87. The drained chemical liquid is recoveredby the chemical liquid circulation unit 100 and is reused for chemicalliquid economization.

Subsequently, the shutter 48 covering the opening 48′ opened, and thechemical liquid supply arm 50 is moved so as to sweep the upper surfaceof the wafer W supported on a spin chuck 59 from the center to theperiphery of the wafer W, blowing N₂ gas, for example, for 10 secondsagainst the upper surface of the wafer W to remove drops of the chemicalliquid from the wafer W. Meanwhile, N₂ gas is blown through the fluidpassage 75 of the under-plate 63 into the gap between the under-plate 63and the lower surface of the wafer W to expel the atmosphere of thechemical liquid from the gap. Drops of the chemical liquid can beremoved from the upper and the lower surface of the wafer W by thusblowing N₂ gas. The chemical liquid thus removed from the wafer W isdrained through the cup drain pipe 87, is recovered by the chemicalliquid circulation unit 100 and is reused for chemical liquideconomization.

Then, as shown in FIG. 14, the cup 58 is lowered and the chemical liquidsupply arm 50 is turned again to the position above the wafer W. Thechemical liquid supply arm 50 is moved radially over the wafer W andpours IPA (rec) on the upper surface of the wafer W, for example, for 10seconds. IPA (rec) is supplied through the fluid passage 75 into the gapbetween the under-plate 63 and the lower surface of the wafer W, forexample, for 10 seconds. The IPA (rec) dripped off the wafer W isdrained through the casing drain pipe 93. Then, the chemical liquidsupply arm 50 is retracted into the chemical liquid supply arm housing44 and the shutter 48 is closed.

Subsequently, the shutter 49 closing the opening 49′ of the chambercasing 43 and separating the interior of the rinsing-and-drying armhousing 45 from the processing chamber 43A is opened, and therinsing-and-drying arm 53 is turned to a position above the wafer W. Inthis state, the shutter 48 is kept closed to seal the chemical liquidsupply arm housing 44 in order that the wafer W and therinsing-and-drying arm 53 are protected from contamination with anatmosphere of the chemical liquid discharged through the chemical liquidpouring nozzle 51 of the chemical liquid supply arm 50. Therinsing-and-drying arm 53 is moved so as to sweep the surface of thewafer W rotating at 1000 rpm at least from the center to the peripheryof the wafer W, pouring IPA (pur) onto the upper surface of the wafer W,for example, for 1 seconds at a pouring rate of 1 liters/min. At thesame time, IPA (pur) is supplied through the fluid passage 75 into thegap between the lower plate 63 and the lower surface of the wafer W, forexample, for 1 s at a supply rate of 1 liters/min. the IPA (pur) drippedoff the wafer W is drained through the casing drain pipe 93 and isrecovered by the IPA circulation unit 112. The thus recovered IPA (rec)is reused.

Then, a rinsing process is performed. The rinsing-and-drying arm 53 ismoved to sweep the upper surface of the wafer W, pouring pure water, forexample, for 2 seconds at a pouring rate of 1 liters/min. The wafer W isrotated at a high rotating speed, for example, in the range of about 500to about 1000 rpm higher than that at which the wafer W is rotatedduring the chemical liquid treatment. Pure water poured onto the wafer Wrotating at a high rotating speed can be uniformly spread over theentire upper surface of the wafer W. Pure water is supplied, forexample, for 2 seconds at a supply rate of 1 liters/min through thefluid passage 74 into the gap L₁ between the under-plate 63 and thelower surface of the wafer W, while the under-plate 63 is held at theworking position. Since the wafer W is rotating at a high rotatingspeed, the pure water supplied into the gap L₁ spreads uniformly overthe entire lower surface of the wafer W. In this state the under-plate63 can be cleaned as well as the wafer W. Both the surfaces of the waferW are thus rinsed to wash off the chemical liquid from the wafer W. Thepure water used for rinsing the wafer W is drained through the casingdrain pipe 93. If the quality of the chemical liquid permits, theforegoing rinsing process using pure water may be omitted. After thecompletion of the rinsing process, a drying process is performed, inwhich the wafer W is rotated at a high rotating speed of, for example,1500 rpm higher than that at which the wafer W is rotated in the rinsingprocess to spin-dry the wafer W. While the wafer W is thus rotated at ahigh rotating speed, N₂ gas is spouted onto the upper surface of thewafer W by the rinsing-and-drying arm 53, and N₂ gas is spouted throughthe fluid passage 75 on the lower surface of the wafer W. Thus, theunder-plate 63 is dried as well as both the surfaces of the wafer W.

After the completion of the drying process, the rinsing-and-drying arm53 is retracted into the rinsing-and-drying arm housing 45 and theshutter 49 is closed. Then, the wafer W is carried out of the substratecleaning unit 12. The mechanical shutter 46 closing the opening 46′ ofthe unit casing 42 and the shutter closing the opening 47′ of thechamber casing 43 are opened. Then, the main wafer-carrying mechanism 18advances the carrying arm 34 into the chamber casing 43 to support thewafer W on the carrying arm 34. Then, the carrying arm 34 is raised toreceive the wafer W from the support pins of the spin chuck 59, andcarries the wafer W out of the substrate-cleaning unit 12. Since theunder-plate 63 is located at the waiting position while the maincarrying mechanism 18 carries the wafer W out of the substrate-cleaningunit 12, a sufficiently wide gap is formed between the under-plate 63and the wafer W supported on the spin chuck 59, and hence the wafer Wcan be smoothly transferred from the spin chuck 59 to the carrying arm34.

When necessary, the chemical liquid supply arm 50 is cleaned by thechemical liquid supply arm cleaning device 56 while the chemical liquidsupply arm 50 is housed in the chemical liquid supply arm housing 44.For example, the chemical liquid supply arm 50 is retracted into thechemical liquid supply arm housing 44 after the completion of pouringIPA (rec) on the wafer W, and then the shutter 48 is closed. Then, thechemical liquid supply arm 50 is moved to a predetermined position, andis cleaned by the chemical liquid supply arm cleaning device 56. Duringa cleaning process for cleaning the chemical liquid supply arm 50, theshutter 48 is kept closed to seal the chemical liquid supply arm housing44 so that an atmosphere of the cleaning liquid may not leak into theinterior space of the unit casing 42 and the processing chamber 43A ofthe chamber casing 43. Therefore, even if the wafer W is placed in theprocessing chamber 43A, the chemical liquid supply arm 50 can becleaned. The throughput of the substrate cleaning unit 12 can beincreased by cleaning the chemical liquid supply arm 50, for example,during the rinsing process. The rinsing-and-drying arm 53 housed in therinsing-and-drying arm housing 45 can be cleaned by therinsing-and-drying arm cleaning device 57 in the rinsing-and-drying armhousing 45 to clean the rinsing-and-drying arm 53 when necessary. Forexample, the rinsing-and-drying arm 53 is retracted into therinsing-and-drying arm housing 45 after the completion of spouting of N₂gas on the wafer W, the shutter 49 is closed, the rinsing-and-drying arm53 is located at a predetermined position, and the rinsing-and-dryingarm 53 is cleaned by the rinsing-and-drying arm cleaning device 57.While the rinsing-and-drying arm 53 is being cleaned, the shutter 49 iskept closed to seal the rinsing-and-drying arm housing 45 so that anatmosphere of a cleaning liquid may not leak into the interior of theunit casing 42 and the processing chamber 43A of the chamber casing 43.Therefore, even if the wafer W is placed in the processing chamber 43A,the rinsing-and-drying arm 53 can be cleaned. The throughput of thesubstrate cleaning unit 12 can be increased by cleaning therinsing-and-drying arm 53, for example, during the cleaning process.

In the substrate cleaning unit 12, the shutters 48 and 49 isolate thespaces in which the chemical liquid supply arm 50 and therinsing-and-drying arm 53 are housed from the atmosphere in theprocessing chamber 43A of the chamber casing 43. Accordingly, theprocessed wafer W is not affected by the atmospheres of liquids that maydrip from the nozzles of the chemical liquid supply arm 50 and therinsing-and-drying arm 53 while the chemical liquid supply arm 50 andthe rinsing-and-drying arm 53 are kept at the waiting positions,respectively. The processed wafer W is not also affected by theatmosphere of the cleaning liquid for cleaning the chemical liquidsupply arm 50 and the rinsing-and-drying arm 53 at their waitingpositions. Moreover, the rinsing-an-drying arm 53 will not becontaminated with the atmosphere of the chemical liquid that may dripfrom the chemical liquid supply arm 50 at the waiting position or theatmosphere of the chemical liquid produced while processing the wafer W.

Although the preferred embodiment of the present invention has beendescribed, the present invention is not limited thereto in its practicalapplication. For example, a FFU 122 may be disposed in an upper regionof the interior of the unit casing 42, and an exhaust mechanism 123 maybe incorporated into a lower part of the unit casing 42 as shown in FIG.15. If the atmosphere of the processing liquid leaks from the processingchamber 43A, the leaked atmosphere of the processing liquid flows downtogether with a downflow produced by the FFU 122 and is discharged fromthe unit casing 42 by the exhaust mechanism 123. Thus, the possibilitythat the processed wafer W is contaminated with the atmosphere of theprocessing liquid when carrying the processed wafer W out of the unitcasing 42 is reduced, and the atmosphere of the processing liquid ishardly able to leak from the unit casing 42. The chemical liquid supplyarm housing 44 and the rinsing-and-drying arm housing 45 may be providedwith exhaust mechanism, respectively.

A plurality of deflectors 130 may be attached to the inner surface ofthe side wall of the chamber casing 43 as shown in FIGS. 16 and 17. Aircurrents that flow toward the side wall of the chamber casing 43 aregenerated when the spin chuck 59 or the top-plate 60 rotates. Theplurality of deflectors 130 guide the air currents downward and,consequently, the processing liquid or the atmosphere of the processingliquid are able to flow smoothly downward. Similarly, a plurality ofdeflectors 131 may be attached to the inner surface of the sidewall ofthe cup 58. The plurality of deflectors 131 guide the air currentsdownward and, consequently, the processing liquid or the atmosphere ofthe processing liquid are able to flow smoothly downward.

As shown in FIG. 18, the under-plate shaft 67 connected to theunder-plate 63 may be provided with a fluid passage 140 for supplying achemical liquid, IPA and N₂ gas in its central part, and with fluidpassages 141 for supplying IPA, pure water and N₂ gas in its central andparts around the central part. As shown in FIG. 19, a discharge port 142for discharging a chemical liquid, IPA and N₂ gas may be formed in acentral part of the under-plate 63, and discharge ports 143 a, 143 b and143 c for discharging IPA, pure water and N₂ gas may be formed in acentral part, in parts at a radial distance equal to ⅓ of the radius ofthe under-plate 63 from the center of the under-plate 63 and in parts ata radial distance equal to ⅔ of the radius of the under-plate 63 fromthe center of the under-plate 63, respectively, in a properlydistributed arrangement. Timing of discharging fluids through thedischarge ports 143 a, 153 b and 143 c may be controlled to dischargethe chemical liquid or pure water, IPA or N₂ gas can be graduallydischarged through the discharge ports 143 a, 143 b and 143 c atdifferent times, respectively. For example, when pure water isdischarged through the discharge ports 143 a, 143 b and 143 c, purewater discharged through the central discharge port 143 a urges purewater discharged through the four discharge ports 143 b arranged on acircle of a radius equal to ⅓ of the radius of the under-plate 63 toflow toward the periphery of the wafer W, and pure water dischargedthrough the discharge ports 143 b urges pure water discharged throughthe four discharge ports 143 c arranged on a circle of a radius equal to⅔ of the radius of the under-plate 63 to flow toward the periphery ofthe wafer W. Thus, the pure water discharged through the radially outerdischarge ports can be urged to flow toward the periphery of the wafer Sby the pure water discharged by the radially inner discharge ports.Therefore, the pure water can be forced to flow efficiently with thewafer W kept stationary, and hence the cleaning effect of the pure wateris similar to that of the pure water available when the wafer W isrotated. When the wafer W is rotated, the pure water can be moreefficiently force to flow for a cleaning effect similar to thatavailable when the wafer W is rotated at a higher rotating speed. Thus,the use of the under-plate 63 provided with those discharge ports 143 a,143 b and 143 c is suitable for processing a wafer by a process in whichthe wafer W cannot be rotated at a high rotating speed.

When discharging N₂ gas through the discharge ports 143 a, 143 b and 143c, N₂ gas is discharged first through the central discharge port 143 ato dry a central part of the surface of the wafer W. After a dryingprocess using the N₂ gas discharged through the central discharge port143 a has been completed, a drying process in which N₂ gas is dischargedthrough the discharge ports 143 b on the circle of the radius equal to ⅓of the radius of the under-plate 63 is started. When the discharge of N₂gas through the discharge ports 143 b is started after a drying processfor drying a central region of the surface of the wafer W inside thecircle on which the discharge port 143 b are arranged has beencompleted, liquid drops adhering to a region of the surface of the waferW outside the circle on which the discharge port 143 b are arranged donot flow to the dried central region of the surface of the wafer W, andhence the drying process can be efficiently carried out. When thedischarge of N₂ gas through the discharge ports 143 c is started afterthe drying process using N₂ gas discharged through the discharge port143 b has been completed, liquid drops adhering to a region of thesurface of the wafer W out side the circle on which the discharge port143 c are arranged do not flow to the dried region of the surface of thewafer W dried by the N₂ gas discharged through the discharge ports 143 aand 143 b, and hence the drying process can be efficiently carried out.Thus, the cleaning process can be efficiently carried out with the waferW kept stationary, and hence the drying effect of the drying process issimilar to that available when the wafer W is rotated. Thus, the use ofthe under-plate 63 provided with those discharge ports 143 a, 143 b and143 c is suitable for drying a wafer by a process in which the wafer Wcannot be rotated at a high rotating speed.

When a liquid, such as IPA or pure water, or a gas, such as N₂ gas isdischarged through the discharge ports 143 a, 143 b and 143 c formed inthe under-plate 63 as shown in FIG. 19, the area of a region allocatedto the radially outer discharge port is larger than that allocated tothe radially inner discharge port. Therefore, the discharge rate or thedischarge pressure at which the fluid to be discharged through theradially outer discharge port may be higher than that of the fluid to bedischarged through the radially inner discharge port. Discharge ratesand/or discharge pressures at which the fluid is discharge through thedischarge ports 143 a, 143 b and 143 c may be increased in order of thedischarge ports 143 a, 153 b and 143 c, which enables efficient, uniformprocessing of the wafer W. In addition to or instead of discharging thefluid at such discharge rate and/or discharge pressures, the number ofthe discharge ports far from the center of the under-plate 63 may beincreased. For example, eight discharge ports 143 c may be formedinstead of the four discharge ports 143 c shown in FIG. 19.

The present invention is not limited to the substrate cleaning apparatusthat uses a cleaning liquid; the present invention is applicable tosubstrate processing apparatus that process substrates by processes thatuse various processing liquids other than cleaning processes. Thesubstrates are not limited to semiconductor wafers and may be glassplates for LCDs, printed wiring boards and ceramic substrates.

In the foregoing embodiment, the space where the processing fluid supplyarm is held at the waiting position and the space where the substrate isprocessed can be isolated from each other. Even if an atmosphere of theprocessing liquid or a processing gas is discharged from the processingfluid supply arm, the atmosphere of the processing liquid or theprocessing gas does not contaminate the other processing liquid supplyarms stored in the processing liquid supply means housing unit. Aprocessing liquid of a high cleanliness can be supplied onto a substrateby cleaning the processing liquid supply arm. The exertion of aninfluence on a substrate placed in the processing chamber by theatmosphere of the cleaning liquid for cleaning the processing liquidsupply arm can be prevented and a processing liquid of a highcleanliness can be always supplied onto a substrate.

Since the substrate-processing system has a double-casing structure anda substrate is processed in the processing chamber defined by thechamber casing, even if an atmosphere of the processing liquid leaksfrom the chamber casing, the leakage of the atmosphere of the processingliquid from the substrate-processing system can be prevented bydischarging the atmosphere of the processing liquid from the unitcasing. When wetting the upper surface of a substrate with theprocessing liquid, the top-plate extending over the substrate so as tocover the substrate prevents the evaporation of the processing liquidforming a processing liquid film on the upper surface of the substrate.The flow of atmosphere of the processing liquid into a space extendingover the top-plate can be prevented by filling the space extending overthe top-plate with an inert gas. When the substrate is subjectedsuccessively to different processes, it is possible to avoid theremaining of the processing atmosphere of the preceding process aroundthe substrate at the start of the succeeding process by carrying out thepreceding process in the space surrounded by the cup, and lowering thecup before starting the succeeding process.

1. A substrate processing apparatus comprising: a substrate supportmember that supports a substrate; an enclosure structure enclosing thesubstrate support member, and provided with an opening; a shutteradapted to move vertically between a raised position where the shuttercloses the opening to define a closed processing space together with theenclosure structure, and a lowered position where the shutter does notclose the opening to allow the substrate to be transferred to and fromthe substrate support member through the opening; a top-plate adapted tomove in the processing space between a first position where thetop-plate is close to an upper face of the substrate supported by thesubstrate support member and a second position where the top-plate isremote from the upper face of the substrate supported by the substratesupport member, wherein the enclosure structure has a top wall arrangedabove the top plate and wherein when the top-plate is located at thefirst position, a space between the top-plate and the substrate held bythe substrate support member and a space between the top wall of theenclosure structure and the top-plate communicate with each otherthrough a space around a periphery of the top-plate; an inert gas supplyport directed toward an upper surface of the top-plate to supply a spacebetween the top wall of the enclosure structure and the upper surface ofthe top-plate with an inert gas; and an exhaust pipe adapted todischarge a gas in the processing space from a bottom portion of theprocessing space.
 2. The apparatus according to claim 1, wherein thetop-plate is rotatable.
 3. The apparatus according to claim 1 furthercomprising a cup arranged in the processing space and surrounding thesubstrate support member.
 4. The apparatus according to claim 3, whereinthe cup and the substrate support member capable of relative movement.5. The apparatus according to claim 1 wherein the inert gas supply portis located right above the top-plate.
 6. The apparatus according toclaim 1 further comprising: a processing liquid supply nozzle that movesthrough a space between the substrate supported by the substrate supportmember and a top-plate located in the second position thereof to sweepthe upper surface of the substrate while supplying a processing liquidonto the upper surface of the substrate.
 7. A substrate processingapparatus comprising: a substrate support member that supports asubstrate; an enclosure structure enclosing the substrate support memberand defining a processing space, a top-plate adapted to move, relativeto the substrate supported by the substrate support member, between afirst position where the top-plate is close to an upper face of thesubstrate supported by the substrate support member and a secondposition where the top-plate is remote from the upper face of thesubstrate supported by the substrate support member, wherein theenclosure structure has a top wall arranged above the top plate; aninert gas supply port directed toward an upper surface of the top-plateto supply a space between the top wall of the enclosure structure andthe upper surface of the top-plate with an inert gas; and an under-plateadapted to move, relative to the substrate supported by the substratesupport member, between a first position where the under-plate is closeto a lower face of the substrate supported by the substrate supportmember and a second position where the under-plate is remote from thelower face of the substrate supported by the substrate support memberwherein when the top-plate is located at the first position, a spacebetween the top-plate and the substrate held by the substrate supportmember and a space between the top wall of the enclosure structure andthe top-plate communicate with each other through a space around aperiphery of the top-plate.
 8. The apparatus according to claim 7,wherein the inert gas supply port is located right above the top-plate.9. The apparatus according to claim 7 further comprising: a processingliquid supply nozzle adapted to travel in an interior of the enclosurestructure, and adapted to move into a space between the substratesupported by the substrate support member and a top-plate located in thesecond position thereof to supply a processing liquid onto thesubstrate.
 10. The apparatus according to claim 7 further comprising: aprocessing liquid nozzle that moves through a space between thesubstrate supported by the substrate support member and a top-platelocated in the second position thereof to sweep the upper surface of thesubstrate while supplying a processing liquid onto the upper surface ofthe substrate.
 11. A substrate processing apparatus comprising: asubstrate support member that supports a substrate; an enclosurestructure enclosing the substrate support member and defining aprocessing space, a top-plate arranged in the processing space while aperiphery of the top plate is remote from the enclosure structure andadapted to move, relative to the substrate supported by the substratesupport member, between a first position where the top-plate is close toan upper face of the substrate supported by the substrate support memberand a second position where the top-plate is remote from the upper faceof the substrate supported by the substrate support member, wherein theenclosure structure has a top wall arranged above the top plate, whereinwhen the top-plate is located at the first position, a space between thetop-plate and the substrate held by the substrate support member and aspace between the top wall of the enclosure structure and the top-platecommunicate with each other through a space around a periphery of thetop-plate; an inert gas supply port directed toward an upper surface ofthe top-plate to supply a space between the top wall of the enclosurestructure and the upper surface of the top-plate with an inert gas; anda temperature regulator that controls temperature of the inert gas to besupplied by the inert gas supply port.
 12. The apparatus according toclaim 11, wherein the inert gas supply port is located right above thetop-plate.
 13. The apparatus according to claim 11 further comprising: aprocessing liquid supply nozzle that moves through a space between thesubstrate supported by the substrate support member and a top-platelocated in the second position thereof to sweep the upper surface of thesubstrate while supplying a processing liquid onto the upper surface ofthe substrate.
 14. A substrate processing apparatus comprising: asubstrate support member that supports a substrate; an enclosurestructure enclosing the substrate support member and defining aprocessing space, a top-plate arranged to move, relative to thesubstrate supported by the substrate support member, between a firstposition where the top-plate is close to an upper face of the substratesupported by the substrate support member and a second position wherethe top-plate is remote from the upper face of the substrate supportedby the substrate support member; an inert gas supply port that suppliesgas into an area above the top-plate in the processing space; atemperature regulator that controls temperature of the inert gas to besupplied by the inert gas supply port; and a processing fluid supplyunit that supplies a processing fluid onto a substrate supported on thesubstrate support member, wherein the temperature regulator controls thetemperature of the inert gas so that, when temperature of the processingfluid is higher than a room temperature, the temperature of the inertgas is equal to or higher than the temperature of the processing fluid,and when the temperature of the processing fluid is lower than a roomtemperature, the temperature of the inert gas is equal to or lower thanthe temperature the processing fluid.